OBD-II code · Powertrain (generic, extended)
P22A1 NOx Sensor Circuit High (Bank 1 Sensor 2)
NOx Sensor Circuit High (Bank 1 Sensor 2): the signal voltage is above the expected range. Often an open circuit or a short to supply voltage.
Is it safe to drive with P22A1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen signal line
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor
Related codes
- P2216NOx Sensor Circuit High (Bank 2)
- P229ENOx Sensor Circuit (Bank 1 Sensor 2)
- P229FNOx Sensor Circuit Range/Performance Bank 1 Sensor 2
- P22A0NOx Sensor Circuit Low (Bank 1 Sensor 2)
- P22A2NOx Sensor Circuit Intermittent (Bank 1 Sensor 2)
- P22A3NOx Sensor Heater Control Circuit/Open (Bank 1 Sensor 2)
- P22A4NOx Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.